San Ramon received the lowest rainfall in recent years, with just 3.41 inches recorded at the nearest weather station in Dublin during 2013, and 1.59 inches since October.
Mark Strudley, a hydrologist with the National Oceanic and Atmospheric Administration
who studies rainfall and flooding, said the area is stuck between el Nino and la Nina conditions.
"Right now, we're in no man's land," Strudley said. "We're right between those two zones of confidence.
El Nino conditions are rising slightly and would normally bring rain to Northern California, but the forecaster said they're not increasing enough to bring a significant amount of rain.
Being trapped between el Nino and la Nina may in part account for the larger-than-normal number of "Winter Spare the Air" alerts called for recent days, with another called for Saturday.
Rainfall tracking for the San Ramon area only goes back to 2008, but local airports have been recording rainfall amounts since mid-1999. Tracking at the Livermore airport puts the average rainfall at 13.54 inches, with 4.62 inches of rain reported there in 2013. Before then, the lowest amount recorded was 8.82 inches.
Danville, with a tracking station at its library, recorded 5.87 inches of rain in 2013, and 2.9 inches of rain since October.
Mount Diablo recorded 6.56 inches of rain in 2013, more than 2 inches less than the previous record of 8.91 inches set in 1976; the normal average is more than 25 inches.
Dry conditions there may account for the rapid spread of a Sept. 8 fire that burned more than 3,100 acres.
Even though this is the rainy season, Strudley said not to expect conditions to change in the immediate future.
"There's a slight chance that we may get some rain Wednesday night, but that's going to be light," he said.
The NOAA is predicting drought conditions for much of the West through March.
